1. Field of the Invention
The present invention relates to a video-signal processing device connectable to an electronic endoscope, and more particularly relates to a video-signal processing device that intervenes between an electronic endoscope and peripheral equipment such as a television monitor, a video tape recorder, a printer, a video-image processing computer, and so on.
2. Description of the Related Art
The described electronic endoscope comprises a flexible conduit and a video processor to which the flexible conduit is detachably joined.
The flexible conduit has an objective lens system provided at the distal end thereof, and a solid state image sensor such as a CCD (charge-coupled device) associated therewith. An object to be photographed is focused, as an optical image, on a light receiving surface of the CCD image sensor by the objective lens system. The optical image is converted into analog image-pixel signals by the CCD image sensor, and the analog image-pixel signals are successively read out of the image sensor by a CCD driver circuit.
Also, the flexible conduit has an optical guide provided within, and the optical guide terminates at a light-emitting end face at the distal end of the flexible conduit. The video processor also includes an optical guide. When the flexible conduit is joined to the video processor, one end of the optical guide of the video processor is connected to a proximal (base) end of the optical guide of the flexible conduit.
The video processor of the electronic endoscope also has a light source and a collective lens system associated therewith, and light rays emitted from the light source are focused on the other end face of the optical guide of the video processor by the collective lens system. Thus, a front area of the distal end of the flexible conduit is illuminated by the light rays emitted from the light-emitting end face of the optical guide of the flexible conduit.
For reproduction of a photographed image as a color image, for example, an RGB field sequential type color imaging system is introduced in the electronic endoscope. Namely, a rotary RGB color filter is intervened between the light source and the inner end face of the optical guide of the video processor, and the RGB color filter is rotated at a given frequency of rotation. In this manner, an object to be photographed is sequentially illuminated by red light rays, green light rays, and blue light rays. Thus, a red optical image, a green optical image, and a blue optical image are focused on the light receiving surface of the CCD image sensor at given time intervals.
Analog color-image-pixel signals successively read from the CCD image sensor by the CCD driver circuit are fed to the video processor, which processes the analog color-image pixel signals to thereby produce a color video signal. Usually, the video processor of the electronic endoscope is connected to a medical TV monitor designed to ensure electrical security, and a photographed image is reproduced on the medical TV monitor on the basis of the color video signal fed from the video processor thereto.
Nevertheless, the electronic endoscope may be connected to a consumer TV monitor at medical site, but in general the consumer TV monitor is not designed to ensure electrical security i.e., xe2x80x9celectrical securityxe2x80x9d being both confidentiality and to insulate a patient from stray current on the signal line.
On the other hand, it is sometimes described to connect an electronic endoscope to other peripheral equipment (such as a video tape recorder, a printer, an image-processor and so on) other than a TV monitor. To this end, the video processor of the electronic endoscope is arranged to output at least two kinds of color video signals. However, in this case, the peripheral equipment are not designed to ensure electrical security.
Furthermore, a user may want to connect the electronic endoscope to a peripheral remotely located from the electronic endoscope. For example, at a large hospital of more than two buildings, there may be a case where a color video signal must be fed from the electronic endoscope used in a room of a first building to a peripheral located at a room of another building. In this case, the video signal should be fed as a digital video signal from the electronic endoscope to the peripheral because an analog video signal is susceptible to attenuation.
Nevertheless, the feeding of the digital video signal to the remote peripheral is not expedient because an expensive parallel signal cable having a plurality of signal lines must be laid therebetween.
Therefore, an object of the present invention is to provide a video-signal processing device connectable to an electronic endoscope such that a video signal is fed from the electronic endoscope to a peripheral equipment such as a TV monitor, a video tape recorder, a printer, an image-processor and so on therethrough, wherein the electronic endoscope can be securely insulated electrically from the peripheral equipment, to thereby ensure electrical security and to protect a patient from stray current on the signal lines.
Another object of the present invention is to provide a video-signal processing device of the above-mentioned type, wherein the video signal can be fed from the electronic endoscope to the peripheral equipment without being considerably subjected to attenuation.
In accordance with an aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope for feeding at least one kind of electric analog video signal from the electronic endoscope to a peripheral equipment, the video-signal processing device comprising an insulation coupler for making it possible to input the electric analog video signal from the electronic endoscope to the video-signal processing device, whereby the electronic endoscope is electrically insulated from the peripheral equipment. The insulation coupler may be a photo-coupler or a transformer coupler.
Preferably, the video-signal processing device further comprises: an analog-to-digital converter for converting the electric analog video signal into a parallel electric digital video signal; a parallel-to-serial converter for converting the parallel electric digital video signal into a serial electric digital video signal; and an electric-optical converter for converting the serial electric digital video signal into a se rial optical digital video signal.
In accordance with another aspect of the presentinvention, there is provided a video-signal processing device connectable to an electronic endoscope for feeding at least one kind of analog component-type color video signal composed of at least three electric signal-components from the electronic endoscope to a peripheral equipment, the video-signal processing device comprising respective insulation couplers for making it possible to input the electric signal-components from the electronic endoscope to the video-signal processing device, whereby the electronic endoscope is electrically insulated from the peripheral equipment. The insulation couplers may be a photo-coupler or a transformer coupler.
Preferably, the video-signal processing device comprises: an analog-to-digital converter for converting each of the electric signal-components into a parallel electric digital signal-component; a parallel-to-serial converter for converting the parallel electric digital signal-components into serial electric digital signal-components; and an electric-optical converter for converting the serial electric digital signal-components into serial optical digital signal-components.
The respective electric signal-components may be a red video signal-component, a green video signal-component, and a blue video signal-component. In this case, the video-signal processing device may further comprise a color-conversion analog matrix circuit for producing a luminance signal-component, and two kinds of color-difference signal-components on the basis of the red, green, and blue video signal-components; an analog-to-digital converter for converting each of the luminance signal-component and two kinds of color-difference signal-components into a parallel electric digital signal-component; a parallel-to-serial converter for converting the parallel electric digital signal-components into serial electric digital signal-components; and an electric-optical converter for converting the serial electric digital signal-components into serial optical digital signal-components.
When the respective electric signal-components are a red video signal-component, a green video signal-component, and a blue video signal-component, the video-signal processing device also may further comprise an analog-to-digital converter for converting each of the red, green, and blue video signal-components into a parallel electric digital color signal-component; a color-conversion digital matrix circuit for producing a parallel luminance signal-component, and two kinds of parallel color-difference signal-components on the basis of the parallel digital color signal-components; a parallel-to-serial converter for converting the parallel electric digital signal-components into serial electric digital signal-components; and an electric-optical converter for converting the serial electric digital signal-components into a serial optical digital signal-components.
The respective electric signal-components may be a luminance signal-component, and two kinds of color-difference signal-components. In this case, the video-signal processing device may further comprise an analog-to-digital converter for converting each of the luminance signal-component and two kinds of color-difference signal-components into a parallel electric digital signal-component; a parallel-to-serial converter for converting the parallel electric digital signal-components into serial electric digital signal-components; and an electric-optical converter for converting the serial electric digital signal-components into a serial optical digital signal-components.
In accordance with yet another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope for feeding at least two kind of electric analog video signals from the electronic endoscope to a peripheral equipment, the video-signal processing device comprising respective two insulation couplers for making it possible to input the two kinds of electric analog video signals from the electronic endoscope to the video-signal processing device, whereby the electronic endoscope is electrically insulated from the peripheral equipment. Each of the insulation couplers may be a photo-coupler or a transformer coupler. Also, one of the two kinds of electric analog video signals is an analog component type color video signal, and the other kind of analog video signal may be a color S-video signal or a composite color video signal.